Aircraft landing gear often are subject to excess energy typically being driven into it's strut assembly resulting in both bottoming the strut as well as exceeding structural limitations on the attached hardware. This often constitutes a hard landing event or some other potential overloading activity.
Airlines are required to fully inspect the landing gear and aircraft if a hard landing event has occurred or has been suspected of occurring. Presently, what is often used to determine whether a hard landing event has occurred is reliance upon the pilot's senses (e.g., feels, hears or possibly sees) during flight, especially during landing and takeoff. Thus, if the pilot feels an unusually large force during landing then this must be reported and either the pilot or other personnel must inspect the landing gear system to determine if an “event” has caused any yielding/deformation to the landing gear or the airplane structure. In present systems, this type of end-of-limit indicator is not readily visible and the triggering of such a indicator may not necessarily or accurately indicate whether an event did occur. Consequently, the fallback position for the airlines in such a situation is to perform an often unwarranted fully detailed inspection of the landing gear system.
The design loads are understood, in the context of the present invention, to mean the maximum loads which the structure of the aircraft can withstand without permanent deformation or damage occurring to the aircraft. For obvious safety reasons, inspection of the structure of the aircraft, as well as repairing possible damage, have to be carried out whenever the prescribed design loads are exceeded. As mentioned above, such an inspection is generally invoked by the pilot, depending on what he/she felt at the moment of the landing and when he/she opines that this landing could have caused real damage to the structure of the aircraft. However, this detection of the loads being exceeded, based only on the subjective determination of the pilot, is often unreliable.
In effect, the reactions perceived at the level of the flight deck often do not accurately convey the real load level applied to the aircraft as a whole. That being so, a significant number of inspections, technically not justified, are invoked by the pilot, which entails inefficient use of time and superfluous expense, heavily penalizing the airline concerned. Considerable loads can be applied to the structure, without, however, giving rise to effects which can be felt at the level of the flight deck. In this case, no inspection is invoked although the aircraft structure could have been damaged, which can then entail grave and irremediable consequences during subsequent flights.